Straight male stud couplings, G/R thread
Threaded fittings
Straight male stud couplings carrying Whitworth pipe threads bridge an inch tapped housing port to a precision steel tube, which is retained by a union nut plus a cutting ring. The range counts 113 versions: ten stud threads from G 1/8" up to G 1-1/2", among them the tapered sizes R 1/8" as well as R 1/4", combined with 23 tube outside diameters from 4 LL to 42 L.
Thread form governs how the joint seals. The parallel inch thread does not seal in the thread flanks at all, it seals on the shoulder against a machined face at the port, whereas the tapered thread seals in the thread itself. At the tube end the series sets the rating: versions on tube 22 L are stated at 160 bar, those on tube 8 S at 630 bar. Materials on offer are zinc plated steel plus stainless steel 1.4571.
Parallel plus tapered inch threads share the same nominal size yet seal at different points, which is why they are no free substitute one for the other. A parallel stud needs a clean flat seat at the port for shoulder plus seal, a tapered stud does without that face. Tube size plus thread size are settled separately: a G 1/4" stud may carry tube 8 S of the heavy series, a G 1" stud a tube 35 L. For repairs the bare body alone often suffices, since nut plus ring stay on the tube.
Power packs, pumps plus control blocks with inch tapped ports, as found on commercial vehicles, agricultural machines, construction equipment as well as on older installed machinery. Further use in rigid pipework on compressors, oil circuits plus cooling lines, on test rigs where heavy series tubes carry loads up to 630 bar. Versions in 1.4571 go into wash down areas as well as process plants.
